KDR and neoplasm: VEGF-A, which induces intracellular signaling through the cell-surface-bound receptors vascular endothelial growth factor receptor (VEGFR)-1 (Flt-1) and VEGFR-2 (Flk-1/KDR) [17], has been identified as a crucial mediator regulating physiological and pathological angiogenesis [18] and, in some instances, survival and repopulation of tumor cells [19,20].